Web inspection improves quality, reduces waste
Q: What current trends in web inspection and defect detection are you noticing and what are their impacts on flexible packaging?
A: There’s definitely a push for 100% inspection. Pricing is coming down, quality is going up and performance is improving.
The balance in any inspection application is between web width, defect size and speed. Those are the variables that drive the cost of the system. If I have to find missing periods on four point type, I need cameras and computers capable of such a fine resolution.
Likewise, if you reduce your defect size, speed tends to also be reduced. Of course, there’s a point where we can achieve speed, web width and defect size, but once we start tilting those variables, everything’s affected. Because web width is fixed, the compromise is either speed or defect size.
Q: Early on, the only printers that used web inspection did so because they were required to do so. With improvements in 100% inspection, what sorts of companies are now using it?
A: Years ago, the web inspection market was very polarized: For example, a pharmaceutical company had to have it, so they had it. But companies creating bags or other products that were not highly scrutinized weren’t using it. Now, however, that ground between these two groups is shrinking. There are quality printers who use 100% inspection for their own internal quality control.
Likewise, the types of companies getting into web inspection are those who would like to say to their customers that they’ve taken it to the next level. They take the fact that they’re doing that extra step to their customers and say, “Look, we can guarantee that what we’re sending you is going to be inspected and meet your standards for quality.”
Remember, too, there’s that customer who is in the middle ground and is currently saying, “Next year or the year after, I want to go into pharmaceutical.” Even if they don’t currently have pharmaceutical customers, they’re taking the steps now to position themselves in those markets that require or strongly encourage 100% inspection.
Q: What are some defects or aspects that your customers are inspecting and looking out for?
A: Missing periods or other punctuation is important. As an example, if a dosage is supposed to be 2.0 mg of morphine and all of a sudden that period is gone, it’s now 20 mg.
On the quality side, they’re looking for broken characters. But because some fonts are a little tighter than others, we have a formula that we use to determine what level of detection is required based on different fonts that they’re using.
At the same time, they also want to inspect for defects in the background and defects in the graphics. Defect detection systems today have that capability to define what a defect is-and reject false positives-in the different areas.
The other thing they’re looking for is color. There are different ways to evaluate color. There are the pure ways, through spectrophotometers and other instruments that provide a definitive value for that color. The printer’s customer has a specific color that, with allowance for variation, is considered acceptable. During the process, the web detection system is looking for the change in value to drop below a point that’s too light or rise above a point that’s too dark, and will alert the operator prior to unacceptable product.